There are two series of drawings, handsome black and whites as well as colored plates which are assigned to Helen Winchester as artist. The outline drawings were made by Pilsbry himself. The collection illustrated two articles published in the Bulletin of the American Museum of Natural History. The first series belongs to the paper entitled, The Aquatic Mollusks of the Belgian Congo by H. A. Pilsbry and J. Bequaert, issued in 1927. The second series illustrates, The Land Mollusks of the Belgian Congo collected by The American Museum in that area in 1909-1915, v. 40, 1919.

These drawings were stored by the American Museum of Natural History until 1960, when through the courtesy of W. K. Emerson they were returned to the Academy. R. T. Abbott culled the drawings and retained only the important ones which were archived Nov. 1, 1960.